Barcode readers often have fixed focus optics because mechanical focusing systems lack robustness to mechanical shocks, among other issues. The result is that scanners have limited depth of field, and the onus is on a user to position the object within that depth of field.
Additionally, the acceptable processing time for barcode readers is very short, as they are used in high-throughput settings such as grocery checkout counters. As such, there is a need to develop barcode readers that allow for a larger scanning depth of field while (a) still being robust to mechanical shocks and/or (b) providing a rapid response to the user.
Light field imaging array systems allow a user to capture four dimensional (4D) images that provide additional imaging information than can be provided by typical imaging systems. For example, a light field imaging array system can provide both spatial and angular light ray information. Two such technologies are lenslet based and camera array based light field systems.
However, one drawback to these systems is that the extra data takes more time to process than in traditional two dimensional (2D) image sensors. For example, a light field imaging camera can be used to distinguish an object in the foreground of the image from an object in the background. However, to do so, the image data must be analyzed and the foreground and background data identified. In some applications, this additional processing can take too long for the technology to actually be beneficial.
For example, typically, when light field imaging array systems are utilized, the image data is analyzed, segmented into parts, and several re-focused images are created wherein each corresponding image is focused on different depths within the image as a whole. In order to do this, an objective function (e.g. sharpness) is maximized over the several re-focused images in order to determine the one providing highest contrast, and corresponding to the depth of the barcode in the scene.
An alternative to this approach is to analyze the scene in the Fourier domain, but this is slow because a large matrix must be transformed into the Fourier domain. The processing time of these methods can be slower than is desirable, in some applications.
Further, in the field of barcode technology, the barcode reader, in many implementations, needs to be durable and in that respect the moving parts of some imaging systems, used to create a larger depth of field, can be detrimental to their usage in this field. Readers also, typically, need to scan and provide the information from the barcode quickly and, as such, barcode identification array systems based on light field cameras have not been able to process data fast enough to be beneficial in this field of technology.